Translation guide
A very large city, typically with a population over 10 million. In Japanese, the concept is expressed with specific terms, often used in urban planning or geography contexts.
Referring to a very large city, especially one with over 10 million people, in a general or academic context.
The most direct translation, used in formal and academic contexts. Literally 'giant city'.
Tokyo is one of the world's leading megacities.
Loanword from English, commonly used in media and casual conversation.
The population of megacities continues to grow.
Means 'large city' or 'metropolis'. Not as specific as 'megacity', but often used in similar contexts.
Traffic congestion is a problem in large cities.
Emphasizing the extended urban region, including suburbs and satellite cities.
Refers to a metropolitan area or urban agglomeration. Often used in statistics and planning.
The population of the Tokyo metropolitan area is about 37 million.
Loanword from English 'megalopolis', used for a chain of roughly adjacent metropolitan areas. Technical term.
巨大都市 (kyodai-toshi) is the native Japanese term and sounds more formal or academic. メガシティ (megashiti) is a loanword and is often used in news or casual contexts. Both are understood, but 巨大都市 is preferred in official documents.
The infrastructure of this megacity is aging.
New technologies are tested in megacities.
If you just want to say 'big city' without the technical connotation of 'megacity', 大都市 (daitoshi) is a safe choice. It covers most large cities, not only those with 10+ million people.
Tokyo is a megacity with over 30 million people.
Megacities face unique environmental challenges.
The Tokaido megalopolis is Japan's largest urban agglomeration.